Solve for $r$ : $-2 = 12 + r$
Answer: Subtract $12$ from both sides: $ \begin{eqnarray} \\ \hphantom{-2 {- 12}} &\hphantom{=}& \hphantom{r} \\ -2 &=& 12 + r \\ \\ {-12} && {-12} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ -2 {- 12} &=& r \\ \end{eqnarray} $ Simplify. $ r = -14$